Elwes began his producing career with 1984's Oxford Blues starring Rob Lowe and Ally Sheedy and has enjoyed continuing success in film. His earlier roles include Men at Work with Emilio Estevez and Charlie Sheen, The Chase with Charlie Sheen, Kristy Swanson, and Henry Rollins, and The Dark Backward with Judd Nelson, Bill Paxton, and Rob Lowe. In 1988 he produced the independent film Never on Tuesday which featured a cast of cameos including Charlie Sheen, Emilio Estevez, Judd Nelson, Nicolas Cage, and Cary Elwes.
On 29 October 2013 Elwes launched the Cassian Elwes Independent Screenwriter Fellowship, in conjunction with The Black List, to award one Writer an all-expenses-paid trip to the 2014 Sundance Film Festival and mentorship from Elwes. Elwes and The Black List plan to award the fellowship annually.
